December is usually filled with articles about Christmas trees and other common festive greenery. The genus Mahonia doesn’t usually make that list, but this might be because of the sometimes spiky leaves it can have. The horticulture industry over the last decade has made great breeding strides to bring this evergreen shrub into the Southeastern landscape.

Introduction

Mahonia is a group of mostly shrubby, upright plants with evergreen, compound leaves, and sweet-smelling yellow to orange flowers. They are popular for their mostly winter-flowering habitat, evergreen presence, tolerance of tough soils, and unique texture in the landscape. It gets its common name, grapeholly, from the holly-like appearance of its leaves, and the grape-like fruits in the spring. It is in the Berberidaceae family, which you can verify by scratching the bark and looking at the yellow vascular tissue. Chemical scientists are interested in the various chemicals that cause this yellow coloration, because they are very biochemically active.

There are approximately 60 to 80 species around the world. There are centers of diversity in Asia, the Pacific Northwest of North America, Central America, and western South America. Many of the Asian species have been in cultivation in the United States for decades, but botanical gardens and plant explorers have been bringing them into cultivation.

Mahonia bealei, Leatherleaf Grapeholly

If you look out in the woods in the wintertime in North Carolina, you may spot a large, upright evergreen shrub with sweet yellow flowers. European honey bees are commonly seen visiting the winter flowers on warm days. It is most likely Mahonia bealei, as there are very few native evergreen shrubs in the piedmont region of the Southeast. Unfortunately, this species is a known invasive exotic plant that has escaped from human landscapes into what is left of natural areas near where we live. Those pollinators working hard in the winter help the plants produce a crop of “grapes” in the summer, and the birds quickly eat and drop the seeds as they fly from site to site. The seeds quickly germinate and crowd out native species. Upon closer look, the aggressively-toothed, leathery leaves make it clear it is safe from browsing animals, making it almost ecologically bullet-proof.

Exotic invasives are known to cause habitat degradation through vegetation cover changes and decreasing plant species diversity. It is important to report invasive plant species on your property for scientists, policy makers and land managers, and to remove them as soon as you can. You can report your findings to the Early Detection and Distribution Mapping System at the University of Georgia. It is still legal to propagate and sell Mahonia bealei in North Carolina, so beware when you go to your local garden center.

Mahonia eurybracteata, Feathery Grapeholly

The horticultural world was taken by storm when Soft Caress, Mahonia eurybracteata ‘Soft Caress’, hit the market in 2010. A seedling selection by botanists and horticulturists in Georgia, it was a vast improvement on the grapehollies in the industry at the time that would grow to be large, bulky plants and had sharp, uncomfortable leaves. Like the name says, it was soft to the touch, both on the hand and on the eye. The texture was so dense and feathery, and the stature perfect for compact areas. It is still evergreen, has beautiful yellow flowers, and is tough like the invasive M. bealei, but not prone to seeding around. The cultivar (“cultivated variety”) has remained popular since, but there have been even more growers producing the species from seeds to great effect for the home gardener.

Mahonia ilicina

A cloud of tiny flowers caught my eye in the back of the Lathe House at the JC Raulston Arboretum. It was a Mahonia, but none I had ever seen! What was a footnote in the curator’s article in the Spring 2013 JCRA newsletter, the Mahonia ilicina specimen now was a tangle of limbs, dark blue leaves, and  countless sprays of flowers. This species is only found in northeastern Mexico, and is barely mentioned in the scientific literature outside of some trip reports from the late 1800s. Maybe it might be the next big thing though!

Visiting botanical gardens is an important habit for gardeners of every level. They are repositories of horticulture knowledge and plant material, and can inspire gardeners throughout the seasons. The JCRA in Raleigh, NC, has one of the most diverse plant collections in the United States, despite its modest footprint.

Cultures around the world, through the millennia have valued the presence of something green in the dark months of the year to remind us life will return in the spring. Mahonia could be your next garden addition for extra winter presence in your garden or to fill in that tough spot in your yard. There are so many non-invasive landscape plant options from the genus, and they are usually readily available at your local garden center.

References:

Flora of China entry for the genus Mahonia

World Flora Online Entry for Mahonia

Invasive Plant Atlas entry for Mahonia bealei

Allen, et al. 2006- When Landscaping Goes Bad: The Incipient Invasion of Mahonia bealei in the Southeastern United States

Greim and Kiage 2021- Abundance and distribution of invasive woody shrub, Mahonia bealei, in the urban forest fragments of the southern Piedmont, USA

Patent Application for ‘Soft Caress’ Mahonia eurybracteata:

JCRA’s Spring 2013 Newsletter with Mahonia ilicina

Amanda Wilkins is the Horticulture Agent for North Carolina Cooperative Extension in Lee County.